While various types of pre-formed multi-layered structure members have been used in the construction field, there is nevertheless a need for a skeletal structural system composed of components which are relatively light in weight, easily transported to the construction site, and readily assembled to provide a strong and rigid framework for a protective dome. Ideally, such a structure would also be capable of being readily dismantled. The dome might be used as temporary shelter for expositions or for construction sites in extreme climates, as an enclosure for radar antennae, radio telescopes, or grain storage depots, as a cover for stadiums, swimming pools, park areas, and the like.
Accordingly, it is an object of this invention to provide a dome framework formed principally of arcuate beam elements which are formed of components which arrive at the construction site in flat or linear form. Another object is to provide a dome structure in which the major frame elements take the form of arcuate support beams, each beam having a lightweight longitudinally-curved core sandwiched between a pair of arcuate strips of material having high tensile and compressive strength.
Another object of this invention lies in providing a method of erecting a dome structure having a framework composed of arcuate support beams, wherein each of the support beams is developed on site by first securing a straight, elongated, flexible core to one side of a narrow skin or strip having high compressive and tensile strength, then longitudinally flexing the strip and core to force the side of the core opposite from the strip into convex configuration, and then securing a second flexible strip of high compressive and tensile strength to the convex side of the core. In the formation of a dome, each such composite beam becomes one of a multiplicity of arcuate struts radiating outwardly and downwardly from the apex of the dome. Each core member and the lower strip to which it is secured are first joined to a central member or hub, before any flexure of the strut takes place, and the second or upper strip of each strut is similarly secured to one end to the hub but is otherwise left unsecured to the core therebelow. Thereafter, the hub is raised from the ground or other supporting surface and the outer ends of the outwardly-radiating partially-formed struts are drawn inwardly towards the axis of the hub to develop a curvature in each core and lower strip and to produce the general dome configuration. As the final steps of the construction of the basic framework, the outer ends of the upper strips are drawn downwardly towards the fixed ends of the arcuate cores and lower strips, and such upper strips, now having been flexed into arcuate configuration, are rigidly secured along their lengths to the core structures.
Other features, objects, and advantages will become apparent from the specification and drawings.